San Francisco Frontiers - Epic pool rivalry lights up first day of Olympic medal action

Fourteen golds are up for grabs, with the first to come in the mixed-team 10-metre air rifle finals, taking place around 10:30 am local time (0830 GMT).

Tennis, badminton, rowing, cycling, hockey and basketball get under way along with the surfing competition, nearly 16,000 kilometres (9,950 miles) kilometres away on the French Pacific island of Tahiti.

Rugby sevens is already at the semi-final stage, with hosts France, led by Antoine Dupont, desperate to win gold in front of a packed and passionate Stade de France crowd.

All eyes will be on the Paris La Defense Arena for the women's 400m freestyle -- one of the most-anticipated events of the entire Olympics involving three swimmers who have held the world record.

Australia's defending champion Ariarne Titmus will dive in as favourite after clocking the second-fastest time ever last month behind only her own 3min 55.38sec world best.

She stunned US rival Katie Ledecky in an electric Tokyo final three years ago, with the American great gunning for revenge.

The two go head-to-head in heat three in the morning session.

"I'm looking forward to the 400m free, day one. I like my chances," said the American, who is the undisputed queen over 800m and 1500m.

"I feel like I'm prepared and ready to race and that's all you can ask for."

Canadian teenage sensation Summer McIntosh, also a former world record holder, completes the hotly favoured trio.

Other gold medals on offer on the first night of action in the pool come in the men's 400m freestyle and the men's and women's 4x100m freestyle relays.

- Swiatek, Alcaraz in action -

Reigning French Open champions Iga Swiatek and Carlos Alcaraz are among the top draws on the first day of action on the clay courts of Roland Garros.

Women's world number one Swiatek is first on court against Romania's Irina-Camelia Begu, with Alcaraz to follow against Lebanese world number 275 Hady Habib.

But the biggest focus will be on the men's doubles, with Alcaraz teaming up with 14-time French Open champion Rafael Nadal in a Spanish dream pairing.

Chinese shooters Huang Yuting and Sheng Lihao will start as favourites for the first gold of the Games after a dominant victory at last year's world championships in Baku.

Medals will also be up for grabs early Saturday in the diving pool, with the women's synchronised 3m springboard final, where another Chinese pairing, Chang Yani and Chen Yiwen, are favourites to strike gold.

The first cycling medals of the games will be decided with the men's and women's individual times trials taking place on a challenging 32.4-kilometre course.

The event will start and finish on Paris's golden Pont Alexandre III and head east to the Bois de Vincennes, sweeping past landmarks such as Notre Dame and the Place de la Bastille.

French rugby fans will flock to the Stade de France to see if Dupont can lead the host nation to gold in rugby sevens.

France however must overcome South Africa in Saturday's semi-finals to reach the gold medal match against the winner of the other last-four clash between holders Fiji and Australia.

Yuto Horigome of Japan is defending his skateboarding street crown as he aims to fend off challengers including Nyjah Huston of the United States and France's Aurelien Giraud.

T.Martin--SFF